Corrosion inhibited motor oils



United btates 2,833,713 Patented May 6, 1958 ice CORR'DSIQN INHIBITED MOTOR OILS No Drawing. Application April 18, 1955 Serial No. 502,222

3 Claims. (Cl. 252-323) This invention pertains to improved lubricant compositions and more particularly pertains to internal combustion engine lubricant compositions which inhibit cam follower'pitting and/ or wear and which inhibit the sticking of hydraulic valve-lifters.

- Many modern automobile engines are designed with hydraulic valve-lifters for smoother and more efiicient engine operation. In the operation of hydraulic valvelifters, the lifter rise on the cam shaft converting the rotary motion of the cam into a reciprocating motion, which in turn opens and closes the valves. The bottom Of the valve-lifter is known as the cam follower. The hydraulic part of the valve-lifter functions by means of a plunger on the inside of the. valve lifter barrel, together with a ball-check and a spring. To obtain higher efficiency and greater horsepower, larger valves, higher valve spring pressures and camshafts which produce more rapid valve opening and closing are employed. In the operation of such engines, greatly increased pressures are encountered where the camshaft lobes come into contact with the faces of the valve-lifters resulting in excessive and severe cam and lifter wear as well as pitting of the cam followers. This wear and/ or pitting cannot be adequately inhibited by most present-day internal combustion engine crank-case lubricants. Surprisingly, the type of antiwear properties which will inhibit piston ring and/or cylinder wear are not necessarily the same as the anti- Wear properties necessary to prevent cam and lifter wear and/ or pitting; hence many lubricants which are effective in inhibiting ring and cylinder Wear are ineffective in preventing cam and lifter wear. A further complicating factor in this problem is caused by the materials used in making the camshaft and valve-lifters since different metals and metal combinations are used for this purpose in the various engines. Camshaft and valve-lifter combinations of different metals create different requirements on the lubricant in that certain types of anti-wear additives may be efiective with some cam-lifter metal combinations but ineffective with other metal combinations. Furthermore, because of the small clearances between the plunger and the barrel of hydraulic valve-lifters, extremely small amounts of deposits such as varnish and/or rusting may cause sticking of the valve-lifter. Hence, it is essential for good engine operation to provide a lubricant which will, in addition to inhibit wear and/or pitting, also inhibit the formation of varnish and/or rusting in the valvelifter;

. ,Itis'an object of this invention to provide a lubricant composition which will not cause sticking of'hydraulic valve-lifters and which 'will inhibit cam .follower wear and/or, pitting. :Another object of the inventionis to provide a crank-case lubricant which will be substantially free of any tendency to cause valve-lifter sticking and which will have cam follower anti-pitting and anti-wear properties. Another object of the invention is to provide an improved lubricant for internal combustion engines. Still another object of the invention is to provide a method of preventing the sticking of hydraulic valve-lifters and the pitting and/or wear of cam followers in internal combustion engines. Other objects and advantages of'the invention will become apparent from the following description thereof. V I

In accordance with the herein described invention,'the above objects can be attained by incorporating in a viscous oil, i. e. an oil having a Saybolt Universal viscosity above about seconds at F., from about 0.05% to about 3% of a mixture of high molecular weight unsaturated fatty acids obtained as a by-product stil lno in the manufacture of sebacic acid by the distillation' jof castor oil in the presence of sodium hydroxide. A rnethod of obtaining such ,by-product still-residues in thepreparation of sebacic acid is described in U. S. 2,47Q,849 ifssued to W. E. Hanson, May 24, 1949. The mixture of high molecular weight unsaturated fatty acids comprises monomers, dimers, trimers and higher polymers in the ratio of from about 45% to about 55% of a monomers and dimers fraction having a molecular weight in therange of from about 300 to 600, and from about 45% to about 55% of a trimers and higher polymer fraction having a molecular weight in excess of 600. The fattyacid polymers result in part from a thermal polymerization ,of fatty acid type constituents of the castor oil, and inpart from other reactions, such as the inter-molecular ester ification, of such acid to form high molecular weight products. The acid mixture, which is mainly a mixture of polymeric long chain polybasic carboxylic acids, is

further characterized by the following specifications:

Acid No to 164. Saponification No to 186. Free fatty acids 75 to 82%. Iodine value 44to 55. Non-saponifiables e 2.5% to 5% A fatty acid mixture such as above described isrnarketed by the W. C. I-Iardesty Company under the trade name D50 acids, and as VR-l acids by Robin and Haas Company. Lubricant compositions containing small amount of D-SO acids have exhibited excellent anti-wear and/or pitting properties as well as anti-rust properties. I 4 v Since as stated above, camshafts and valve-lifters'are frequently fabricated of combinations of different metals which may not be equally responsive to any one inhibitor, a series-of tests are required to determine the suitability of any one compound for the inhibition of rusting and/or wear of'valve-lifters and camshaft followers. 'lfhe fpllowing tests have been usedto evaluate the wearand/or rusting inhibiting properties of the above described lubricant additive.

I. CADILLAC TEST made.

165 F. and a load of grade horsepower. In the Cadillac cold test, the test period is 50 hours with a cycle of two hours running and two hours off. The engine is operated at 1,000 R. P. M. with a water outlet temperature of 100 F. and a load of 0 brake horsepower. An unleaded fuel composed of 90% straight run naphtha and alkylate is used. At the end of the test period, the cam-lifter surfaces are examined and wear measurements II. 180 F. CHEVROLET TEST III. CHRYSLER TEST This test is carried out in a Chrysler V-8 engine equipped with chilled cast iron cam followers and an alloy cast iron camshift andlifters. The engine is operated for 120 hours with a two hours on and a one hour ofi cycle at 1200 R. P. M. with a water outlet temperature of 165 F. and a load of 0 brake horsepower. At the end of the test period, the cam lifters are examined for pitting and measured for wear.

IV. BUICK HOT TEST This test is the same as the Cadillac hot test except that a Buick engine is used.

V. MODIFIED INDIANA HYDRAULIC VALVE- LIFTER RUST TEST This test is carried out in a Chevrolet Powerglide engine operating at 2500 R. P. M. and a load of 45 B. H. P. with an oil temperature of 120 F. and a water temperature of 85-95 F. The test engine is operated at these conditions for hours with a 4 hour running and 4 hour off cycle. At the end of 20 hours the dipstick, rocker arm shaft and valve lifters are inspected for rust. Valve lifters free of rust are rated 10 and badly rusted lifters are rated 1.

The effectiveness of the herein described mixture of high molecular weight unsaturated fatty acids in inhibiting corrosion and/ or rusting is demonstrated by the data in Table I. These data were obtained by subjecting (1) a solvent extracted SAE 10 motor oil base and (2) the oil of (1) containing 0.16% of the fatty acid mixture designated D-50 Acids to the above described tests.

amounts of from about 0.002% to about 10%, and preferably from about 0.01% to about 5%. Among the phosphorus and sulfur-containing addition agents are the neutralized reaction products of a phosphorus sulfide and a hydrocarbon, an alcohol, a ketone, an amine or an ester. Of the phosphorus sulfide reaction product addi tives, the neutralized reaction products of a phosphorus sulfide, such as a phosphorus pentasulfide, and a hydro-- carbon of the type described in U. S. 2,316,082, issued to C. M. Loane et al. April 6, 1943, are preferred.

As taught in the U. S. 2,316,082 patent, the preferred hydrocarbon constituent of the reaction is a mono-olefin hydrocarbon polymer resulting from the polymerization of low molecular weight mono-olefin hydrocarbons, such as propylene,butenes, amylenes or copolymers' thereof. Such polymers may be obtained by the polymerization of mono-olefins of less than 6 carbon atoms in the pres ence of a catalyst, such as sulfuric acid, phosphoric acid, boron fluoride, aluminum chloride or other similar halide catalysts of the FriedeLCrafts type.

The polymers employed are preferably mono-olefin polymers or mixtures of mono-olefin polymers and isomono-olefin polymers having molecular Weights ranging from about 150 to about 50,000 or more, and preferably from about 500 to about 10,000. Such polymers can be obtained, for example, by the polymerization in the liquid phase of a hydrocarbon mixture containing monoand isomono-olefins, such as butylene and isobutylene at a temperature of from about F. to about F. in the presence of a metal halide catalyst of the Friedel- Crafts type, such as for example, boron fluoride, aluminum chloride, and the like. In the preparation of these polymers, a hydrocarbon mixture containing isobutylene, butylenes and 'butanes recovered from petroleum gases, especially those gases produced in the cracking of petroleum oils in the manufacture of gasoline can be used.

Another suitable polymer is that obtained by polymerizing in the liquid phase, a hydrocarbon mixture comprising substantially C hydrocarbons in the presence of an aluminum chloride-complex catalyst. The catalyst is preferably prepared by heating aluminum chloride with iso-octane. The hydrocarbon mixture is introduced into the bottom of the reactor and passed upward through the catalyst layer, while a temperature of from about 50 F. to about F. is maintained in the reactor. The propane and other aturated gases pass through the catalyst while the propylene is polymerized under these con ditions. The propylene polymer can be fractionated to any desired molecular weight, preferably from about 500 to about 1000, or higher. I

Essentially paraffinic hydrocarbons, such as bright stock residuums, lubricating oil distillates, petrolatums, or par- Table I Cadillac Test, Hydraulic Valve Litter Sample inches F. Chrysler Buick Rust Test N0. Chevrolet; Test, Test, Test inches inches Cold Hot DS 1 HAS 2 VL 3 1 0.001 0.002 10 0.006 0.002 Mod- Mod i 5.5 I

pi e 2 0. 0003 0. 0003 Perfect.-- 0.003 0.0003 Clean- S1..- 9. 5

IDS=dipstick. RAS=rocker armshaft. 1 VL=valve lifters. 10=perfect.

afiin waxes, can be reacted with the phosphorus sulfide, as well as high molecular weight olefinic hydrocarbons such as cetene (C cerotene (C melene (C and mixed high molecular weight alkenes obtained by cracking petroleum oils.

Other preferred olefins suitable for the preparation of thephosphorus sulfide reaction products are olefins having at least 20 carbon atoms in the molecule of which from about 13 carbon atoms to about 18 carbon atoms,

and preferably at least 15 carbon atoms, are in a long chain. Such olefins can be obtained by the dehydrogenation of alkyl halides, preferably long chain alkylhalides, particularly halogenated pa'raffin waxes.

As a starting material there can be used the polymer or synthetic lubricating oil obtained by polymerizing unsaturated hydrocarbons resulting frorn the vapor phase cracking of parafiin waxes'inthe presence of aluminum chloride which is fully described in U. S. Patents 1,955,260,1,970,402and2,091,398; Other hydrocarbons that can be reacted with a phosphorus sulfide are aromatic hydrocarbons, such as for example, benzene, naphthalene, toluene, xylene, diphenyl and the like, or an alkylated aromatic hydrocarbon, such as for example, benzene having an alkyl substituent having at least 4 carbon atoms, and-preferablyatleast 8 carbon atoms, such as a long chain parafiin wax.

The phosphorus sulfide-hydrocarbon reaction product can be readily obtained by reactinga phosphorus-sulfide, for example, P S with the hydrocarbon at atemperature of from about 200 F. to about 500 F., and preferably from about 200 F. to about 400 F., using from-about 1% to about 50%, and preferably from about 5% to about 25% of the phosphorus sulfide in the -reaction; It is advantageous to maintain a non-oxidizing atmosphere, such as for example, an atmosphere of nitrogen above the reaction mixture. use an amount of the phosphorus sulfide that'will'complctely react with the hydrocarbon so that no further purification becomes necessary; however, an excess amount of phosphorus sulfide can be used and separated from the productjby filtration or by dilution "with a hydrocarbon solvent, such as hexane, filtering and subsequently removing the solvent by suitable means, such as by distillation. If desired, the reaction product can Usually, it is preferable. to

be further treated with steam at an elevated temperature of from about 100 F. to about 600 F. The phosphorus sulfide-hydrocarbon reaction product normally shows a titratable acidity which is neutralized by treatment with a basic reagent. The phosphorus sultide-hydrocarbon reaction product when neutralized with a basic reagent containing a metal constituent is characterized by the presence 'or retention ofthe metal constituent of the basic reagent. Prior to neutralization the reaction product can be hydrolyzed and clayed to remove inorganic acids of phosphorus as described in U. S. 2,688,612 issued to R. W. Watson'September 7,1954.

The neutralized phosphorus sulfide-hydrocarbon reaction product can be obtained by treating theacidic reaction product with a suitable basic compoundfsuch' as hydroxide, carbonateoxide or sulfide of an alkaline earth metal or an alkali metal, such as for example, potassium hydroxide, sodium hydroxide, sodium sulfide, calcium oxide, lime, barium hydroxide, barium oxide, etc. basic reagents can be used, s'uch"as for'example, am-

monia or an alkyl or aryl-substituted ammonia, suchas" amines. The neutralization of the phosphorus sulfidehydrocarbon reaction product is carried out preferably in a non-oxidizing atmosphere by contacting the acidic'reaction product either as such or'dissolved in a suitable Other solvent, such as naphtha with asolution of the basic agent. As an alternative method the reaction product can be treated With solid alkaline compounds, such as KOH, NaOI-I, Na CO K CO CaO, BaO, Ba(OH) Na s, and the like, at an elevated temperature of from about 100 F. to about 600 F. Neutralized reaction products containing a heavy metal constituent, such as for example, tin, titanium, aluminum, chromium, cobalt, zinc, iron, and the like, can be obtained by reacting a salt of the desired heavy metal with the phosphorus sultide-hydrocarbon reaction product which has been treated with a basic reagent such as above-described.

Other phosphorus sulfide reaction products which can be used are the reaction products of a phosphorus sulfide and a fatty acid ester of the type described in Viscosity determined immediately afterblendlngt-w and turpentine of U; $51,409,877 and U.'S;2,409,878;

the reaction product of a phosphorus sulfideandstearonitrile of U. S. 2,416,807, etc. i

' The high molecular weight unsaturated fatty acid mixture and the sulfur and/or phosphorus and sulfur-containing detergent type additive can be added individually to the basemotor oil -or-' :they can he pre-mixed in 'sthe desired proportions preferably in the proportion ofi from about 1% to about 30% of .the-fattyacid materiaL-and from about 99% to about 70% of the defined detergenttype additive, at a temperature of about 70 F. to about 150 F..and the resultant mixed product added to ..the base oil. 1 Because of the complexities-of the compounds concerned it-hasnot'been possible to 'determine definitely what takes place: when the fatty acid"mixtureand"the defined detergent-type additive-are heated together. There is'some indication that there is'some' interaction'between the two, with the probable formation of-a complex, since the viscosity of heated blends of the components is higher than' either of the-components It "has" been observed that with heated blends of the'fatty acid mixture and-a barium neutralized reaction product of P S and a polybutene of about 1000 molecular weight a maximum -viscosity' increaseis obtained with a blend of 20% of "the former and of the latter. This viscosity' increase is illustrated by the "data inTable II.

Table II VISOOSI'IIES OF BLENDS -[Visc'oslty, SUS at 210 F.]

Compositlon, Theoretical, '8 Hrsrnfter 'Wt, Percent Blending --Ifrom Vislendin Blend N o. Temp, cosity Blend- Room Temp. a F. ing Chart storage A B T 100 0 349 349 99 1 150 350 372' 98 2 150 351 376 97 3 150 352 397 96 4 150 353 412 5 I50 354 464 94 6 150 355 5499 93 7 150 356 582 92 8 150 357 630 91 9 150 358 .718 90 10 1 50 359 757 80 20 150 364 844 70 30 150 -375 ,692 60 40 150 383 627 50 50 150 398 563 40 60 150 3405 v522 30 70 150 418 506 20 80 150 420 I475 10 90 150 439 A56 0 1152 452 80 a 20 70 I364 ,840

A-Barium-conteinlng neutralized, hydrolyzed and elayed V reaction pr duct of P255 and a polybutene of about 1000 molecular weight.

While such detergent-type additives effectively inhibit the formationof sludge and/or varnish-like products';in the engine they-donot possess"corrosionand/orrusting inhibiting properties or anti-wear properties. However, when used in combination with the herein described mixture of high molecular weight unsaturated fatty acids complete engine protection is obtained. This is demonstrated by the data in Table III in which performance tests are tabulated together with the so-called conventional 'were subjected to the tests in Table III: Sample A.-So'lvent extracted SAE 10 Oil.

, 8 We claim: V I V 1. A lubricating oil composition comprising a major proportion of a hydrocarbon lubricating oil and from about 0.05 to about 3% of a mixture comprising essen- Sampla B? Sa mp1e A+4'3% of a fi i i 5 tiallypolymeric long chain unsaturated polybasic-car neutralized reaction product of P S and a polybutene of P- f Sald F mlxture Fompnsmg m i about 1000 molecular weight +.75 of a sulfurized di- 22 1 5 52 5: z gg f g i gg 31 21323: igs

@ r01 ou ooao la 1 r' :gg Sulfur)+ slhcone polymer mmdimer fraction having a molecular weight in the range of V 10 from about 300 to about 600 and from about 45% to Sample C.--Sample B+0.16% D-50 Acid. about 55% of a trimer and higher polymer fraction having Table III Cadillac Test," Hydraulic vnve Lifter x inches 180 F. Chrysler Buick L- l Rust Test ,,S ample No. Chevrolet Test, Test, Test. Test inches inches 1,; Cold Hot DS 1 RAS I w. 8

A 0.001 0.002 10 heavy 0. 006 0.002 Fall... Mod Mod.-.. 5.5 0.001 0.002 nfi fi ilu 0.006 0.002 Pass-.-. Sever-0.- Severe-.' 5.5

0. 0003 0. 0003 perieeL-.- 0. 003 0. 0003 do---- Clean-.. Slight--- 9.5

4 Supra (Table I).

It will be noted from the above data that the oil cona molecular weight in excess of 600 and from about taining the detergent additive passed the L-4 test but was 0.002% to about 10% of an alkaline earth-containing no better than the base oil alone in the other tests, and neutralized reaction product of a phosphorus sulfide and even somewhat less efiective than the base oil in the valvean olefin polymer. lifter rust test. However, the oil containing the detergent 2. A composition as described in claim 1 in which the additive in combination with the mixture of high molecuneutralized reaction product is a barium-containing neular weight unsaturated fatty acids was effective in all the tralized reaction product of a phosphorus sulfide and a tests and had no deleterious effect on the copper-lead butylenepolymer. bearings in theL-4 test. 3. A lubricating oil concentrate comprising essentially I Concentrates of a suitable lubricating oil base containa viscous hydrocarbon oil and more than 10% of a mixing,10% to about 50% or more of the herein described ture comprising essentially polymeric long chain unsatmixture of high molecular weight unsaturated fatty acids, urawd Polybasic carboxylic d Said acid mixture alone, or in combination with more than 10% of other prising monomers, dimers, trimers and higher fatty acid additives, such as detergent-type additives, can be used for I I polymers in the ratio of from-about 45% to about 55% blending with other hydrocarbon lubricating oils or other 40 0f a'monomer and dimer fraction having a molecular lubricating oil bases in the proportions desired for the W ight in he r nge of fr about 300 to about 600 n particular conditions of use to give a finished product confrom about to about 55% of a trimer and higher taining from about 0.05% to about 3% of the mixture of polymer fraction having a molecular weight in excess of .high molecular weight unsaturated fatty acids. about and o than Of n lin arth-C011- While the present invention has been described by the 45 "taining neutralized reaction product of a phosphorus suluse of the mixture of fatty acids in petroleum lubricating and l Olefin P y Said Concentrate i g Capa le oils, other lubricating oil bases can be employed such as of dilution with a hydrocarbon oil to form a homogeneous hydrocarbon oils, natural or synthetic such as those obmixture containing fr 095% to 3% 0f Said faity acid tained by the polymerization of olefines, as well as synmixture, and from about 0.002% to about 10% of said thetic'lubricating oils of the alkylene oxide type, for exneutralized phosphorus sulfide-olefin polymer reaction ample Uconoils marketed by Carbide and Carbon Corproduct. poration, and the polycarboxylic acid ester type oils such as the oil-soluble esters of adipic acid, sebacic acid, azelaic Referencis m the fi o thls Patent acid, e i UNITED STATES PATENTS g f f g fg i sg g gl f Stated 2,124,628 Moser July 26, 1938 g n ages- 2,402,825 Lovell et al June 25, 1946 Although the present invention has been described with 2,442,672 Fuchs et a1 June I 1948 reference to specmc preferred embodiments thereof, the 2,470,849 May 24 1949 invention is not to be considered as limited thereto but in- 2 31 979 McDarkott Man 17, 1953 eludes within its scope such modifications and variations 2, 32, Landis Man 24, 5 as come within the spirit of the appended claims. 2,688,612 Watson Sept. 7, 1954 

1. A LUBRICATING OIL COMPOSITION COMPRISING A MAJOR PROPORTION OF A HYDROCARBON LUBRICATING OIL AND FROM ABOUT 0.05% TO ABOUT 3% OF A MIXTURE COMPRISING ESSENTIALLY POLYMERIC LONG CHAIN UNSATURATED POLYBASIC CARBOXYLIC ACIDS, SAID ACID MIXTURE COMPRISING MONOMERS, DIMERS, TRIMERS AND HIGHER FATTY ACID POLYMEES IN THE RATIO OF FROM ABOUT 45% TO ABOUT 55% OF A MONOMER AND DIMER FRACTION HAVING A MOLECULAR WEIGHT IN THE RANGE OF FROM ABOUT 300 TO ABOUT 600 AND FROM ABOUT 45% TO ABOUT 55% OF A TRIMER AND HIGHER POLYMER FRACTION HAVING A MOLECULAR WEIGHT IN EXCESS OF 600 AND FROM ABOUT 0.002% TO ABOUT 10% OPF AN ALKALINE EARTH-CONTAINING NEUTRALIZED REACTION PRODUCT OF A PHOSPHORUS SULFIDE AND AN OLEFIN POLYMER. 